The objective of these studies is to improve the genetics of the cellular slime mold Dictyostelium discoideum so that genetics can be more efficiently used to study the development of cellular adhesion in this organism. Three related projects are being pursued. The first is an effort to increase the number of genetic markers beyond the 20 now available and to label all seven linkage groups. To this end drug resistant mutants are being selected from amoebae growing on axenic agar and the axenic medium is being simplified so that auxotrophs can be isolated. The second project is directed to the isolation of mutants which are affected in cell adhesion. These mutants will be analyzed genetically and biochemically. An attempt will be made to assess the effect of altered glycoproteins and glycosyltransferases on cell adhesion. The third project is directed toward an understanding of the mutant FR17, which speeds up development in this organism. Preliminary genetic experiments on FR17 will be amplified. New mutants resembling FR17 will be isolated and used to test the effect of this mutant on developmental control. Its effect will be tested genetically and biochemically.